Text entry is the first step of most uses of computers and there will always be a need to enter text faster.
While many users of computers are familiar with keyboard operations, this cannot be assumed of the expanding new classes of users and this has created interest in alternative techniques for text entry, such as voice processing and handwriting recognition. But the problem of speed remains unresolved by these alternative techniques. Handwriting is slower than typing. A skilled typist can be expected to enter around 40 to 70 words per minute, but no voice recognition technique appears close to reaching it while this typing speed remains below the more than 100 words per minute of normal speech. Finally, the speed of speech is itself below the speed of reading--well beyond 200 words per minute--and we are known to recognize certain elements of text at far higher speeds, measured in thousands of words per minute.
So the limitations of the speed of text entry contribute to the frustration of users of computers when there may be more than a factor of ten between the time it takes to form an idea and keying it into a computer. Many high-level users therefore consider the use of computers as too slow and, in particular, as slowing down the thought process.
Several techniques have been tried in the past to accelerate text entry. These present techniques fall into the so-called categories of word-completion and macros.
Word-completion
Word-completion allows the user to type the initial letters of a word and let the computer system do the completion. A good example of word-completion was offered by the Spell key of the formula editor of a commercial spreadsheet called Javelin, released in 1984. When a Javelin user types a few letters and presses the Spell key, Javelin either completes the name or gives a list of possible names that match what was typed so far: If there is only one name that matches, completion is done automatically and the name is inserted; if two or more names match what was typed so far, Javelin displays a menu of possible choices. Selection of one of the menu choices is then done using cursors or a mouse, or by adding letters and pressing Spell again.
Similar word-completion techniques have been offered in many other commercial software products, such as word-processors and spelling checkers, for at least the past ten years. An early example was the spelling checker included with Microsoft Word, a word processor released around 1983.
The major drawback of word completion techniques comes from the fact that the root of a word (its first letters) is usually not a very good way to discriminate among several alternative words. For example, there are several hundred words starting with the root "con", and therefore any meaningful choice will require at least a fourth letter. Even with a fourth letter, there are more than a hundred words that start with "cont" or with "cons" and more than fifty that start with "const". So in practice, the root has to be sufficiently long to reduce the number of possible choices to ten or less, a number small enough to allow easy selection. Consequently, word completion fails to achieve a significant reduction in the number of keystrokes.
Several techniques have been proposed to overcome these limitations. For example, U.S. Pat. No. 4760528 offers a system of abbreviation based on the uses of abbreviated prefixes and suffixes. Similarly, U.S. Pat. No. 4893238 offers an abbreviation technique based on syllables. Neither these, nor other similar techniques based on strict abbreviation rules, have been very successful in practice. Both patents claim to achieve a reduction in the number of keystrokes entered that is in the range of 1.3 to 1.4. But most potential users consider this reduction to be insufficient to justify learning a set of strict abbreviation rule.
To achieve a higher reduction payoff requires other techniques and, in particular, it requires using abbreviations for phrases, not just for words, a domain addressed mostly with macros in the past.
Macros
Macros are an even older concept, first published in 1958 by Christopher Stratchey. With macros, a user can define abbreviations for certain (usually long) phrases or words, type the abbreviation and request its expansion with a special key. For example, the abbreviation "dj" may be defined for "Dow Jones Industrial Average" and then typing the two letters "dj" followed by the special key has the effect of expanding the abbreviation, that is, of replacing it by the corresponding text.
Commercial products offering this kind of macro capability appeared very early on microcomputers. Prokey, released in 1983, is an early example of such products. Similar macro capabilities were also incorporated in early versions of word-processors such as Microsoft Word (1983) and XyWrite. The names used for these facilities vary widely with the products and so do the special keys used for requesting expansion. Prokey allowed the user to select which key to use for expansion. A number of recent products use a single space as the key for expansion. For example, this is done in the Windows version of Microsoft Word (1994), with the so-called Autocorrect feature: having defined the abbreviation "asap", it may be expanded into "as soon as possible" when a space is typed after the final letter of "asap". A similar facility is offered in XyWrite and in WordPerfect version 6.1.
The above examples would suggest that macros have the potential to provide reduction factors higher than the 2 or 3 that is the minimum required to reach the speed of slow or moderate speech. But in practice the use of macros is severely limited by the difficulty of learning, remembering, and applying systematically such macros. So the facility tends to be used for a few favorite phrases--usually less than a hundred--, which means that its overall effect on input speed is only marginal. Both word-completion and macros fall short of offering a viable solution for fast text entry.